What each digit is worth, including decimals
In 5th grade, children learn that each place in a number is worth ten times the place to its right, including decimals, so 0.09 is one tenth of 0.9.
By Robert “Bobby” BarnettMath teacher, parent, and founder of Bobby’s Math Club
Try these with your child
These are real questions from our 5th grade practice. Tap the speaker to hear one read aloud, or the light bulb for a hint, and talk about the answer together.
Question 1 of 3
How many hundredths are in 1 tenth?
- 10
- 1/10
- 100
Why this matters
Once this idea clicks, decimals start to make sense for your child. Seeing that each place is worth ten times the one to its right turns multiplying by 10, rounding money, and lining up decimals into one idea instead of separate tricks. Without it, decimals can feel like rules to memorize, which makes percentages and measurement in middle school harder than they need to be.
Where kids can get stuck
- Believing the pattern works only for whole numbers, so they know 70 is ten times 7 but not how 0.7 and 0.07 relate.
- Mixing up the direction, so they say the 4 in 0.04 is worth more than the 4 in 0.4.
- Treating the decimal point as a wall, reading 3.33 as "three and thirty-three" instead of 3 ones, 3 tenths, and 3 hundredths.
How you can help
- Lay out a dollar bill, a dime, and a penny on the table. Ask your child how many dimes make a dollar and how many pennies make a dime, then talk about how each is one tenth of the one before.
- Pick a price at the store, like $4.44, and ask your child what each 4 is worth: four dollars, four dimes, four pennies. Ask how many times bigger the dollar 4 is than the dime 4.
- Measure something with a ruler marked in centimeters and millimeters. Point out that 10 millimeters make 1 centimeter, so a millimeter is one tenth of a centimeter, the same pattern as tenths and hundredths.
If it’s helpful, you can sign up for free, adaptive practice in Bobby's Math Club.
Questions parents ask
Why is my child learning place value this way in 5th grade?
Your child already knows place value for whole numbers. Fifth grade makes the pattern explicit: every place is ten times the one to its right. Once that idea is solid, decimals stop being a separate topic and become the same system continued past the decimal point. Teachers focus on the relationship between places because memorizing place names alone does not help with decimal arithmetic.
How can I explain that 0.09 is one tenth of 0.9?
Use money. 0.9 of a dollar is 9 dimes, or 90 cents. 0.09 of a dollar is 9 pennies, or 9 cents. Nine cents is one tenth of ninety cents, because a penny is one tenth of a dime. Laying the coins out lets your child see the size difference rather than taking it on trust.
Why does my child struggle with decimals when they are fine with whole numbers?
Many children carry whole-number habits into decimals, such as thinking a longer number is a bigger number. Understanding that each place is one tenth of the place to its left helps fix that. It often takes repeated experience with money, measuring, and pictures of tenths before it settles, and that is a normal part of learning this skill.
Make learning math fun
Bobby's Math Club turns 5th grade math practice into something fun to do together.
- Unlimited free practice
- Practice that starts where your child is and grows with them
- You see their progress and what to work on next
Written by Robert “Bobby” Barnett
Bobby is an award-winning math teacher, the author of Meet Every Learner’s Needs, and the father of two elementary-school math learners. He uses Bobby’s Math Club with his own kids a few times every week. Learn more or contact Bobby.
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Join the clubNote for teachers: This skill is covered by Common Core math standard 5.NBT.A.1: “Recognize that in a multi-digit number, a digit in one place represents 10 times as much as it represents in the place to its right and 1/10 of what it represents in the place to its left.” Learn how Bobby's Math Club can help your students grow. (Common Core 5.NBT.1)